Dangerous wild animals: species guidance

Crocodilians

Species names

Alligatoridae  - alligators and caimans
Crocodylidae – crocodiles and the false gharial
Gavialidae - gharial or gavial

Additional information

All crocodilian species require a licence.

There are 23 known crocodilian species. This guidance provides basic safety and husbandry information for the group, however it is recommended that keepers research species-specific husbandry information before applying for a licence.

Conservation status

Most species of crocodilian are classified as Annex A species under EC Regulation 338/97 (relating to the Convention on Trade in Endangered Species (CITES)).  

Special permits must be obtained to buy, sell, breed or use Annex A species for any commercial purpose.

Housing overview

Crocodilians require an enclosure with fresh water, dry land, appropriate heating and of adequate size. Most crocodilians grow longer than 2m, and require sufficient water to be able to submerge themselves. 

All crocodilians are cold-blooded, which means that they cannot regulate their body temperature internally. Therefore enclosures must be heated to a comfortable temperature for the species kept. They are likely to be housed indoors.

Keepers should be able to show that they have adequate space for fully-grown members of the species they plan to keep.

Keeping experience

In order to protect the welfare of these animals and to protect keeper and public safety, keepers must be able to demonstrate a good knowledge of husbandry and handling of the species they wish to keep.

There should be a second named person on the licence who is competent to care for the animals should the owner be absent or incapacitated.

Housing recommendations

Construction

A tank with a lid is suitable for hatchlings, however this is only temporary housing and will not remain appropriate for long. Juvenile and adult crocodilians will require a secure enclosure with both water and land.

Crocodilians are strong, and can climb and dig well. Enclosures should be solid enough to cope with this behaviour.

All enclosures should have a smaller holding facility, to allow keepers to safely enter enclosures to clean, and to permit the veterinary treatment of the animals if necessary. 

Any concrete or artificial flooring used should be non-slip.

Outdoor enclosures are not suitable for crocodilians in Scotland.

Fencing

Fencing or walls of enclosures must be strong enough to withstand the weight of the reptiles climbing on it or jumping against it and, if a mesh is used, its size used must be small enough to prevent the animals becoming entangled. Fence or wall height must be of an adequate height to stop the reptile getting out. Fences of a minimum of 1.5m high, with 0.5m inward slant will prevent the escape of all but the largest specimens.

The fencing or walls should be set into concrete foundations to prevent the reptiles digging, or pushing underneath.

Size

The minimum space required for crocodilians is determined by the size of each animal. For a pair of crocodilians, it is recommended that the minimum area of dry land should be three times the final length of the largest animal by four times the length of the largest animal. The minimum water area should be four times length by five times length, and at least 0.3 times the length of the reptile deep. 

Example for two crocodiles, each 2m long:

• land area – minimum recommended area is 6m x 8m (48m²)
• water area – 8m x 10m (80m²) and at least 0.6m deep

The minimum land space provided should be increased by 10% for each additional reptile in the enclosure, and the minimum water area provided should be increased by 20%.

The enclosure should be large enough to allow the reptiles to walk around, dry themselves, bask in a warmer area, cool off, submerge themselves and swim.

Temperature and shelter

The preferred body temperatures ranges between 29 to 34°C. Enclosures should provide a temperature gradient allowing the reptiles to reach their preferred body temperature, and to cool down if needed. Temperature in the enclosure should range from 26°C to 36°C.

American and Chinese alligators can tolerate lower temperatures, but are comfortable at the lower end of the range listed.

Lighting

Crocodilians require a day-light cycle with 11 to 13 hours of light. The use of full-spectrum light bulbs are recommended. A spotlight for basking should be provided.

Ventilation

Enclosed holding quarters should have a suitable form of ventilation.

Drainage

The drainage must be capable of rapidly removing all excess water, and to prevent flooding of the pool. Drains should be designed to avoid injury to the animals. Any open drains, other than those carrying surface water, should be outside the enclosure. Any faecal material must be disposed of in an environmentally sound manner.

Cleanliness

Enclosures should be maintained in a clean state, with faeces and food debris being removed on a regular basis. A water filtration system appropriate to the size of the water pool and animal stock is necessary to keep the water clean. The pool should be emptied and cleaned at least once every two weeks.

Water quality should be tested regularly to prevent ammonia build-up, and appropriate measures should be taken to maintain a reasonable water quality.

A separate holding enclosure should be incorporated that allows the keeper to enter safely to clean and maintain the main enclosure.

Social dynamics and behavioural considerations

Crocodilians can be kept in groups, however it is important to have enough room for the whole group. Species should not be mixed.

In the wild, these reptiles will form loose social groups, often dominated by one male that excludes other males.

If more than one animal is kept, some provision should be made to separate them if necessary. This would normally be in the form of a divider in the holding enclosure.

Prevention of escape

Crocodilians can climb well, therefore the inside surface of enclosure walls should be smooth. Items in the enclosure must be placed far enough away from the walls that they cannot be used as steps.

Crocodilians can move surprisingly quickly over land. It is therefore strongly recommended that keepers do not enter the enclosure on their own, or without some way of fending off the reptiles.

Food, drink and bedding

These reptiles require a meat diet. Fish can also be fed, but must be supplemented appropriately with vitamins. Whole prey items should preferably be fed, including the skin and bones, however chicken portions including the bones are suitable. The feeding of live vertebrate prey is prohibited. Adult crocodilians do not require feeding every day. If food is left uneaten, it should be removed from the enclosure. 

Bedding material for these animals is not normally required.

Visiting interval

The animals must be monitored at appropriate intervals, normally at least once every 24 hours.

Exercise and enrichment

Crocodilians tend not to be very active, however sufficient pool space must be available to allow the animals to swim, and sufficient land space to allow the animals to bask and to move around.

Provision for capture and transportation

For large crocodilians, there should be some method of enclosing the animals into a holding pen, to allow the safe cleaning of the enclosure and the administration of veterinary treatment. It is recommended that the door mechanisms for these holding pens should be operable from outside the enclosure. 

Veterinary treatment should be provided on-site.

A licence, issued by the local authority, for the keeping of these animals may specify restrictions on the movement of these animals and procedures to be followed. Specially constructed transport crates will be required.

Emergency planning

There should be a written contingency plan in place to be used in the event of an emergency, for example fire, flood, animal escape or injury to the keeper.

Notification requirements

The licence may also specify procedures to be followed in the event of an escape and on the provision of information to the emergency services.

You are required to notify the local authority of any intentions to breed the animals.

Prevention and control of spread of disease

Some provision should be made to allow the separation of sick or injured animals if a group is kept.

The keeper should provide details of their veterinary arrangements with a practice prepared to treat these animals. A schedule of veterinary care, including routine parasite control is required, and the keeping of records of veterinary attention is essential.

There are no transmissible diseases carried by these animals that pose a risk to the general public if they do not directly handle the animals or their by-products. Keepers should be aware of the risk of salmonellosis from handling reptiles, which they in turn could pass on to family members if good hygiene is not observed. Thorough hand washing following the handling or cleaning out of any reptile is recommended.